Note: This is abouth the original, not the Rebirth, which I haven’t played.
This is a game that was taken down by Nintendo for having “questionable religious content”. Since Steam doesn’t have the same restrictions, it now has a new life.
The religious content? Well, remember the story where God asks Abraham to sacrifice his son? That’s known as Binding of Isaac. This game has the same starting point: Isaac’s Mom is asked by God to kill Isaac. Isaac, however, escapes through a hatch and fights back through the basement.